ARM: EXYNOS: Handle of of_iomap() failure

Prevent possible NULL pointer dereference if of_iomap() fails.
Handle the error by skipping such power domain.
Signed-off-by: NKrzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: NKukjin Kim <kgene@kernel.org>

arch/arm/mach-exynos/pm_domains.c

@@ -138,6 +138,14 @@ static __init int exynos4_pm_init_power_domain(void)
 		pd->pd.name = kstrdup(dev_name(dev), GFP_KERNEL);
 		pd->name = pd->pd.name;
 		pd->base = of_iomap(np, 0);
+		if (!pd->base) {
+			dev_warn(&pdev->dev, "Failed to map memory\n");
+			kfree(pd->pd.name);
+			kfree(pd);
+			of_node_put(np);
+			continue;
+		}
+
 		pd->pd.power_off = exynos_pd_power_off;
 		pd->pd.power_on = exynos_pd_power_on;